All cash

 I get cash from a tenant on the rural property. I take the cash to the local grocer, put cash on account.

No  banks, just paper. I am unbanked, due to my tax issue. This systems works fine, low cash, rapid transactions. When I shop we ring it up and I walk away, the paper block chain ledger handles it all. Scofflaw costs covered in goods price, simple, short cut; but it requires an intelligent store manager, a pit boss.  I could make this a contract if I had smart card, eliminate the paper notebook.   

This is the deal with bearer assets, a huge gain in transaction efficiency, sandbox needs it. But there is no Black-Sholes for this, the yields are contained in a two block walk to the store. So the random events are entirely me and the shopkeeper's hours and a few others in the neighborhood.